Baltazar, A., Aranda, J.I., González-Aguilar, G., 2008. Bayesian classification of ripening stages of tomato fruit using acoustic impact and colorimeter sensor data Computers and Electronics in Agriculture 60, 113–121.

Baltazar, A., Aranda, J.I., González-Aguilar, G., 2008. Bayesian classification of ripening stages of tomato fruit using acoustic impact and colorimeter sensor dataComputers and Electronics in Agriculture60, 113–121.)| false
• Search Google Scholar
• Export Citation

Baranyai, L., Zude, M., 2008. Analysis of laser light migration in apple tissue by Monte Carlo simulation Progress in Agriculture Engineering Sciences 4, 45–59.

Baranyai, L., Zude, M., 2008. Analysis of laser light migration in apple tissue by Monte Carlo simulationProgress in Agriculture Engineering Sciences4, 45–59.)| false
• Search Google Scholar
• Export Citation

Baranyai, L., Zude, M., 2009. Analysis of laser light propagation in kiwifruit using backscattering imaging and Monte Carlo simulation Computers and Electronics in Agriculture 69, 33–39.

Baranyai, L., Zude, M., 2009. Analysis of laser light propagation in kiwifruit using backscattering imaging and Monte Carlo simulationComputers and Electronics in Agriculture69, 33–39.)| false
• Search Google Scholar
• Export Citation

Bron, I.U., Ribeiro, R.V., Azzolini, M., Jacomino, A.P., Machado, E.C., 2004. Chlorophyll fluorescence as a tool to evaluate the ripening of 'Golden' papaya fruit Postharvest Biology and Technology 33, 163–173.

Bron, I.U., Ribeiro, R.V., Azzolini, M., Jacomino, A.P., Machado, E.C., 2004. Chlorophyll fluorescence as a tool to evaluate the ripening of 'Golden' papaya fruitPostharvest Biology and Technology33, 163–173.)| false
• Search Google Scholar
• Export Citation

Carrara, S., Pardossi, A., Soldatini, G.F., Tognoni, F., Guidi, L., 2001. Photosynthetic activity of ripening tomato fruit Photosynthetica 39, 75–78.

Carrara, S., Pardossi, A., Soldatini, G.F., Tognoni, F., Guidi, L., 2001. Photosynthetic activity of ripening tomato fruitPhotosynthetica39, 75–78.)| false
• Search Google Scholar
• Export Citation

Chen, H., De Baerdemaeker, J., 1993. Finite element-based modal analysis of fruit firmness Transactions of the ASAE 36, 1827–1833.

Chen, H., De Baerdemaeker, J., 1993. Finite element-based modal analysis of fruit firmnessTransactions of the ASAE36, 1827–1833.)| false
• Search Google Scholar
• Export Citation

De Belie, N., Schotte, S., Lammertyn, J., Nicolai, B., De Baerdemaeker, J., 2000. PHpostharvest technology: Firmness changes of pear fruit before and after harvest with the acoustic impulse response technique Journal of Agricultural Engineering Research 77, 183–191.

De Belie, N., Schotte, S., Lammertyn, J., Nicolai, B., DeBaerdemaeker, J., 2000. PHpostharvest technology: Firmness changes of pear fruit before and after harvest with the acoustic impulse response techniqueJournal of Agricultural Engineering Research77, 183–191.)| false
• Search Google Scholar
• Export Citation

De Ketelaere, B., Howarth, M.S., Crezee, L., Lammertyn, J., Viaene, K., Bulens, I., De Baerdemaeker, J., 2006. Postharvest firmness changes as measured by acoustic and low-mass impact devices: a comparison of techniques Postharvest Biology and Technology 41, 275–284.

De Ketelaere, B., Howarth, M.S., Crezee, L., Lammertyn, J., Viaene, K., Bulens, I., DeBaerdemaeker, J., 2006. Postharvest firmness changes as measured by acoustic and low-mass impact devices: a comparison of techniquesPostharvest Biology and Technology41, 275–284.)| false
• Search Google Scholar
• Export Citation

DeEll, J.R., Prange, R.K., Murr, D.P., 1996. Chlorophyll fluorescence of Delicious apples at harvest as a potential predictor of superficial scald development during storage Postharvest Biology and Technology 9, 1–6.

DeEll, J.R., Prange, R.K., Murr, D.P., 1996. Chlorophyll fluorescence of Delicious apples at harvest as a potential predictor of superficial scald development during storagePostharvest Biology and Technology9, 1–6.)| false
• Search Google Scholar
• Export Citation

DeEll, J.R., Toivonen, P.M.A., 2000. Chlorophyll fluorescence as an indicator of broccoli quality during storage in modified atmosphere packaging HortScience 35, 256–259.

DeEll, J.R., Toivonen, P.M.A., 2000. Chlorophyll fluorescence as an indicator of broccoli quality during storage in modified atmosphere packagingHortScience35, 256–259.)| false
• Search Google Scholar
• Export Citation

Delwiche, M., McDonald, T., Bowers, S.V., 1987. Determination of peach firmness by analysis of impact forces Transactions of the ASAE 30, 249–254.

Delwiche, M., McDonald, T., Bowers, S.V., 1987. Determination of peach firmness by analysis of impact forcesTransactions of the ASAE30, 249–254.)| false
• Search Google Scholar
• Export Citation

Diezma-Iglesias, B., Ruiz-Altisent, M., Barreiro, P., 2004. Detection of internal quality in seedless watermelon by ícoustic impulse response Biosystems Engineering 88, 221–230.

Diezma-Iglesias, B., Ruiz-Altisent, M., Barreiro, P., 2004. Detection of internal quality in seedless watermelon by ícoustic impulse responseBiosystems Engineering88, 221–230.)| false
• Search Google Scholar
• Export Citation

Diezma-Iglesias, B., Valero, C., García-Ramos, F.J., Ruiz-Altisent, M., 2006. Monitoring of firmness evolution of peaches during storage by combining acoustic and impact methods Journal of Food Engineering 77, 926–935.

Diezma-Iglesias, B., Valero, C., García-Ramos, F.J., Ruiz-Altisent, M., 2006. Monitoring of firmness evolution of peaches during storage by combining acoustic and impact methodsJournal of Food Engineering77, 926–935.)| false
• Search Google Scholar
• Export Citation

Elbatawi, I.E. , 2008. An acoustic impact method to detect hollow heart of potato tubers Biosystems Engineering 100, 206–213.

Elbatawi, I.E. , 2008. An acoustic impact method to detect hollow heart of potato tubersBiosystems Engineering100, 206–213.)| false
• Search Google Scholar
• Export Citation

Fan, L., Song, J., Forney, C.F., Jordan, M.A., 2011. Fruit maturity affects the response of apples to heat stress Postharvest Biology and Technology 62, 35–42.

Fan, L., Song, J., Forney, C.F., Jordan, M.A., 2011. Fruit maturity affects the response of apples to heat stressPostharvest Biology and Technology62, 35–42.)| false
• Search Google Scholar
• Export Citation

Felföldi, J. , 1996. Firmness assessment of fruits and vegetables based on acoustic parameters Journal of Food Physics 58, 39–47.

Felföldi, J. , 1996. Firmness assessment of fruits and vegetables based on acoustic parametersJournal of Food Physics58, 39–47.)| false
• Search Google Scholar
• Export Citation

Felföldi, J., Fekete, A., 2000. Firmness assessment by impact method, ASAE Annual International Meeting, Milwaukee.

Felföldi, J., Fekete, A., 2000. Firmness assessment by impact method, ASAE Annual International Meeting, Milwaukee.)| false
• Search Google Scholar
• Export Citation

Funamoto, Y., Yamauchi, N., Shigenaga, T., Shigyo, M., 2002. Effects of heat treatment on chlorophyll degrading enzymes in stored broccoli (Brassica oleracea L.) Postharvest Biology and Technology 24, 163–170.

Funamoto, Y., Yamauchi, N., Shigenaga, T., Shigyo, M., 2002. Effects of heat treatment on chlorophyll degrading enzymes in stored broccoli (Brassica oleracea L.)Postharvest Biology and Technology24, 163–170.)| false
• Search Google Scholar
• Export Citation

Gómez, A.H., Wang, J., Pereira, A.G., 2005. Impulse response of pear fruit and its relation to Magness-Taylor firmness during storage Postharvest Biology and Technology 35, 209–215.

Gómez, A.H., Wang, J., Pereira, A.G., 2005. Impulse response of pear fruit and its relation to Magness-Taylor firmness during storagePostharvest Biology and Technology35, 209–215.)| false
• Search Google Scholar
• Export Citation

Herppich, W.B. , 2001. Application potential of chlorophyll fluorescence imaging analysis in horticultural research, 6th International Symposium: Fruit, Nut and Vegetable Production Engineering, Potsdam, Germany, pp. 609–614.

Herppich, W.B. , 2001. Application potential of chlorophyll fluorescence imaging analysis in horticultural research, 6th International Symposium: Fruit, Nut and Vegetable Production Engineering, Potsdam, Germany, pp. 609–614.)| false
• Search Google Scholar
• Export Citation

Hitka, G. , 2011. Development of the controlled atmosphere storage technology of apricot. Corvinus University of Budapest, Budapest, Hungary.

Hitka, G. , 2011. Development of the controlled atmosphere storage technology of apricot. Corvinus University of Budapest, Budapest, Hungary.)| false
• Search Google Scholar
• Export Citation

Kosson, R. , 2003. Chlorophyll fluorescence and chilling injury of green pepper as affected by storage conditions Acta Horticulturae 628, 379–385.

Kosson, R. , 2003. Chlorophyll fluorescence and chilling injury of green pepper as affected by storage conditionsActa Horticulturae628, 379–385.)| false
• Search Google Scholar
• Export Citation

Krause, G.H., Weis, E., 1991. Chlorophyll fluorescence and photosynthesis: the basics Annual Review of Plant Physiology and Plant Molecular Biology 42, 313–349.

Krause, G.H., Weis, E., 1991. Chlorophyll fluorescence and photosynthesis: the basicsAnnual Review of Plant Physiology and Plant Molecular Biology42, 313–349.)| false
• Search Google Scholar
• Export Citation

Lu, R. , 2004. Multispectral imaging for predicting firmness and soluble solids content of apple fruit Postharvest Biology and Technology 31, 147–157.

Lu, R. , 2004. Multispectral imaging for predicting firmness and soluble solids content of apple fruitPostharvest Biology and Technology31, 147–157.)| false
• Search Google Scholar
• Export Citation

Mattheis, J.P., Rudell, D., 2011. Responses of d'Anjou' pear (Pyrus communis L.) fruit to storage at low oxygen setpoints determined by monitoring fruit chlorophyll fluorescence Postharvest Biology and Technology 60, 125–129.

Mattheis, J.P., Rudell, D., 2011. Responses of d'Anjou' pear (Pyrus communis L.) fruit to storage at low oxygen setpoints determined by monitoring fruit chlorophyll fluorescencePostharvest Biology and Technology60, 125–129.)| false
• Search Google Scholar
• Export Citation

Maxwell, K., Johnson, G.N., 2000. Chlorophyll fluorescence –a practical guide Journal of Experimental Botany 51, 659–668.

Maxwell, K., Johnson, G.N., 2000. Chlorophyll fluorescence –a practical guideJournal of Experimental Botany51, 659–668.)| false
• Search Google Scholar
• Export Citation

Mitcham, E.J., Crisosto, C.H., Kader, A.A., 1996. Pear, Anjou, Bosc, Comice: Recommendations for maintaining postharvest quality. Department of Plant Sciences, University of California, Davis, Available at: http://postharvest.ucdavis.edu/PFfruits/PearAnjouBoscComice/, Accessed 31 October 2012.

Mitcham, E.J., Crisosto, C.H., Kader, A.A., 1996. Pear, Anjou, Bosc, Comice: Recommendations for maintaining postharvest quality. Department of Plant Sciences, University of California, Davis, Available at: http://postharvest.ucdavis.edu/PFfruits/PearAnjouBoscComice/, Accessed 31 October 2012.)| false
• Search Google Scholar
• Export Citation

Molina-Delgado, D., Alegre, S., Barreiro, P., Valero, C., Ruiz-Altisent, M., Recasens, I., 2009. Addressing potential sources of variation in several non-destructive techniques for measuring firmness in apples Biosystems Engineering 104, 33–46.

Molina-Delgado, D., Alegre, S., Barreiro, P., Valero, C., Ruiz-Altisent, M., Recasens, I., 2009. Addressing potential sources of variation in several non-destructive techniques for measuring firmness in applesBiosystems Engineering104, 33–46.)| false
• Search Google Scholar
• Export Citation

Nedbal, L., Soukupova, J., Whitmarsh, J., Trtilek, M., 2000. Postharvest imaging of chlorophyll fluorescence from lemons can be used to predict fruit quality Photosynthetica 38, 571–579.

Nedbal, L., Soukupova, J., Whitmarsh, J., Trtilek, M., 2000. Postharvest imaging of chlorophyll fluorescence from lemons can be used to predict fruit qualityPhotosynthetica38, 571–579.)| false
• Search Google Scholar
• Export Citation

Peng, Y., Lu, R., 2006. Improving apple fruit firmness predictions by effective correction of multispectral scattering images Postharvest Biology and Technology 41, 266–274.

Peng, Y., Lu, R., 2006. Improving apple fruit firmness predictions by effective correction of multispectral scattering imagesPostharvest Biology and Technology41, 266–274.)| false
• Search Google Scholar
• Export Citation

Peng, Y., Lu, R., 2007. Prediction of apple fruit firmness and soluble solids content using characteristics of multispectral scattering images Journal of Food Engineering 82, 142–152.

Peng, Y., Lu, R., 2007. Prediction of apple fruit firmness and soluble solids content using characteristics of multispectral scattering imagesJournal of Food Engineering82, 142–152.)| false
• Search Google Scholar
• Export Citation

Prange, R.K., DeLong, J.M., Leyte, J.C., Harrison, P.A., 2002. Oxygen concentration affects chlorophyll fluorescence in chlorophyll-containing fruit Postharvest Biology and Technology 24, 201–205.

Prange, R.K., DeLong, J.M., Leyte, J.C., Harrison, P.A., 2002. Oxygen concentration affects chlorophyll fluorescence in chlorophyll-containing fruitPostharvest Biology and Technology24, 201–205.)| false
• Search Google Scholar
• Export Citation

Purvis, A.C. , 2002. Diphenylamine reduces chilling injury of green bell pepper fruit Postharvest Biology and Technology 25, 41–48.

Purvis, A.C. , 2002. Diphenylamine reduces chilling injury of green bell pepper fruitPostharvest Biology and Technology25, 41–48.)| false
• Search Google Scholar
• Export Citation

Qin, J., Lu, R., 2007. Measurement of the absorption and scattering properties of turbid liquid foods using hyperspectral imaging Appl. Spectrosc. 61, 388–396.

Qin, J., Lu, R., 2007. Measurement of the absorption and scattering properties of turbid liquid foods using hyperspectral imagingAppl. Spectrosc.61, 388–396.)| false
• Search Google Scholar
• Export Citation

Qin, J., Lu, R., 2008. Measurement of the optical properties of fruits and vegetables using spatially resolved hyperspectral diffuse reflectance imaging technique Postharvest Biology and Technology 49, 355–365.

Qin, J., Lu, R., 2008. Measurement of the optical properties of fruits and vegetables using spatially resolved hyperspectral diffuse reflectance imaging techniquePostharvest Biology and Technology49, 355–365.)| false
• Search Google Scholar
• Export Citation

Qin, J., Lu, R., 2009. Monte Carlo simulation for quantification of light transport features in apples Computers and Electronics in Agriculture 68, 44–51.

Qin, J., Lu, R., 2009. Monte Carlo simulation for quantification of light transport features in applesComputers and Electronics in Agriculture68, 44–51.)| false
• Search Google Scholar
• Export Citation

Ragni, L., Berardinelli, A., Guarnieri, A., 2010. Impact device for measuring the flesh firmness of kiwifruits Journal of Food Engineering 96, 591–597.

Ragni, L., Berardinelli, A., Guarnieri, A., 2010. Impact device for measuring the flesh firmness of kiwifruitsJournal of Food Engineering96, 591–597.)| false
• Search Google Scholar
• Export Citation

Romano, G., Argyropoulos, D., Nagle, M., Khan, M.T., Müller, J., 2012a. Combination of digital images and laser light to predict moisture content and color of bell pepper simultaneously during drying. Journal of Food Engineering 109, 438–448.

Romano, G., Argyropoulos, D., Nagle, M., Khan, M.T., Müller, J., 2012a. Combination of digital images and laser light to predict moisture content and color of bell pepper simultaneously during drying. Journal of Food Engineering109, 438–448.)| false
• Search Google Scholar
• Export Citation

Romano, G., Baranyai, L., Gottschalk, K., Zude, M., 2008. An approach for monitoring the moisture content changes of drying banana slices with laser light backscattering imaging Food and Bioprocess Technology 14, 410–414.

Romano, G., Baranyai, L., Gottschalk, K., Zude, M., 2008. An approach for monitoring the moisture content changes of drying banana slices with laser light backscattering imagingFood and Bioprocess Technology14, 410–414.)| false
• Search Google Scholar
• Export Citation

Romano, G., Nagle, M., Argyropoulos, D., Müller, J., 2011. Laser light backscattering to monitor moisture content, soluble solid content and hardness of apple tissue during drying Journal of Food Engineering 104, 657–662.

Romano, G., Nagle, M., Argyropoulos, D., Müller, J., 2011. Laser light backscattering to monitor moisture content, soluble solid content and hardness of apple tissue during dryingJournal of Food Engineering104, 657–662.)| false
• Search Google Scholar
• Export Citation

Romano, G., Nagle, M., Müller, J., 2012b. Monitoring physical parameters of tropical fruits suring drying by application of laser light in the VIS/NIR spectrum, CIGRAgEng Valencia, Spain.

Romano, G., Nagle, M., Müller, J., 2012b. Monitoring physical parameters of tropical fruits suring drying by application of laser light in the VIS/NIR spectrum, CIGRAgEng Valencia, Spain.)| false
• Search Google Scholar
• Export Citation

Saquet, A.A., Streif, J., 2002. Chlorophyll fluorescence as a predictive method for detection of browning disorders in Conference pears during controlled atmosphere storage Acta Horticulturae 596, 863–866.

Saquet, A.A., Streif, J., 2002. Chlorophyll fluorescence as a predictive method for detection of browning disorders in Conference pears during controlled atmosphere storageActa Horticulturae596, 863–866.)| false
• Search Google Scholar
• Export Citation

Schotte, S., De Belie, N., De Baerdemaeker, J., 1999. Acoustic impulse-response technique for evaluation and modelling of firmness of tomato fruit Postharvest Biology and Technology 17, 105–115.

Schotte, S., De Belie, N., De Baerdemaeker, J., 1999. Acoustic impulse-response technique for evaluation and modelling of firmness of tomato fruitPostharvest Biology and Technology17, 105–115.)| false
• Search Google Scholar
• Export Citation

Taniwaki, M., Hanada, T., Sakurai, N., 2009a. Postharvest quality evaluation of "Fuyu" and "Taishuu" persimmons using a nondestructive vibrational method and an acoustic vibration technique. Postharvest Biology and Technology 51, 80–85.

Taniwaki, M., Hanada, T., Sakurai, N., 2009a. Postharvest quality evaluation of "Fuyu" and "Taishuu" persimmons using a nondestructive vibrational method and an acoustic vibration technique. Postharvest Biology and Technology51, 80–85.)| false
• Search Google Scholar
• Export Citation

Taniwaki, M., Hanada, T., Tohro, M., Sakurai, N., 2009b. Non-destructive determination of the optimum eating ripeness of pears and their texture measurements using acoustical vibration techniques. Postharvest Biology and Technology 51, 305–310.

Taniwaki, M., Hanada, T., Tohro, M., Sakurai, N., 2009b. Non-destructive determination of the optimum eating ripeness of pears and their texture measurements using acoustical vibration techniques. Postharvest Biology and Technology51, 305–310.)| false
• Search Google Scholar
• Export Citation

Taniwaki, M., Takahashi, M., Sakurai, N., 2009c. Determination of optimum ripeness for edibility of postharvest melons using nondestructive vibration. Food Research International 42, 137–141.

Taniwaki, M., Takahashi, M., Sakurai, N., 2009c. Determination of optimum ripeness for edibility of postharvest melons using nondestructive vibration. Food Research International42, 137–141.)| false
• Search Google Scholar
• Export Citation

Tijskens, L.M.M., van Kooten, O., Otma, E.C., 1994. Photosystem 2 quantum yield as a measure of radical scavengers in chilling injury in cucumber fruits and bell peppers Planta 194, 478–486.

Tijskens, L.M.M., van Kooten, O., Otma, E.C., 1994. Photosystem 2 quantum yield as a measure of radical scavengers in chilling injury in cucumber fruits and bell peppersPlanta194, 478–486.)| false
• Search Google Scholar
• Export Citation

Valente, M., Leardi, R., Self, G., Luciano, G., Pain, J.P., 2009. Multivariate calibration of mango firmness using vis/NIR spectroscopy and acoustic impulse method Journal of Food Engineering 94, 7–13.

Valente, M., Leardi, R., Self, G., Luciano, G., Pain, J.P., 2009. Multivariate calibration of mango firmness using vis/NIR spectroscopy and acoustic impulse methodJournal of Food Engineering94, 7–13.)| false
• Search Google Scholar
• Export Citation

van Kooten, O., Snel, J., 1990. The use of chlorophyll fluorescence nomenclature in plant stress physiology Photosynth Res. 25, 147–150.

van Kooten, O., Snel, J., 1990. The use of chlorophyll fluorescence nomenclature in plant stress physiologyPhotosynth Res.25, 147–150.)| false
• Search Google Scholar
• Export Citation

von Willert, D.J., Matyssek, R., Herppich, W., 1995. Experimentelle Pflanzenökologie. Grundlagen und Anwendungen Thieme, Stuttgart, Germany.

Wanitchang, P., Terdwongworakul, A., Wanitchang, J., Nakawajana, N., 2011. Nondestructive maturity classification of mango based on physical, mechanical and optical properties Journal of Food Engineering 105, 477–484.

Wanitchang, P., Terdwongworakul, A., Wanitchang, J., Nakawajana, N., 2011. Nondestructive maturity classification of mango based on physical, mechanical and optical propertiesJournal of Food Engineering105, 477–484.)| false
• Search Google Scholar
• Export Citation

Woolf, A.B., Laing, W.A., 1996. Avocado fruit skin fluorescence following hot water treatments and pretreatments J. Amer. Soc. Hort. Sci. 121, 147–151.

Woolf, A.B., Laing, W.A., 1996. Avocado fruit skin fluorescence following hot water treatments and pretreatmentsJ. Amer. Soc. Hort. Sci.121, 147–151.)| false
• Search Google Scholar
• Export Citation

Wright, H., DeLong, J., Harrison, P.A., Gunawardena, A.H.L.A.N., Prange, R., 2010. The effect of temperature and other factors on chlorophyll a fluorescence and the lower oxygen limit in apples (Malus domestica) Postharvest Biology and Technology 55, 21–28.

Wright, H., DeLong, J., Harrison, P.A., Gunawardena, A.H.L.A.N., Prange, R., 2010. The effect of temperature and other factors on chlorophyll a fluorescence and the lower oxygen limit in apples (Malus domestica)Postharvest Biology and Technology55, 21–28.)| false
• Search Google Scholar
• Export Citation

Yang, X., Song, J., Fillmore, S., Pang, X., Zhang, Z., 2011. Effect of high temperature on color, chlorophyll fluorescence and volatile biosynthesis in green-ripe banana fruit Postharvest Biology and Technology 62, 246–257.

Yang, X., Song, J., Fillmore, S., Pang, X., Zhang, Z., 2011. Effect of high temperature on color, chlorophyll fluorescence and volatile biosynthesis in green-ripe banana fruitPostharvest Biology and Technology62, 246–257.)| false
• Search Google Scholar
• Export Citation

Zsom-Muha, V., Felfödi, J., 2007. Vibration behavior of long shape vegetables Progress in Agricultural Engineering Sciences 3, 21–46.

Zsom-Muha, V., Felfödi, J., 2007. Vibration behavior of long shape vegetablesProgress in Agricultural Engineering Sciences3, 21–46.)| false
• Search Google Scholar
• Export Citation

Zsom, T., Zsom-Muha, V., Baranyai, L., Herppich, W.B., Felföldi, J., Balla, C., 2010. Nondestructive determination of post-harvest ripening of capsicum × annum Kárpia' Acta Horticulturae 858, 407–412.

Zsom, T., Zsom-Muha, V., Baranyai, L., Herppich, W.B., Felföldi, J., Balla, C., 2010. Nondestructive determination of post-harvest ripening of capsicum × annum Kárpia'Acta Horticulturae858, 407–412.)| false
• Search Google Scholar
• Export Citation